Conventional hand blenders comprise of a motor unit and several separable tool unit. Tool units are used for food processing such as cutting, chopping and blending. The motor drives a tool member, such as a chopper, cutter or blender, via the motor drive shaft, the coupling assembly and the tool drive shaft. The transfer of rotational movement from the motor shaft to the tool member and the transfer of axial, tangential and radial forces from the tool member to the motor shaft, due to the forces invoked by the processing of food, on top of tolerances due to material and geometric properties, lead to margins between the several elements of the hand blender. The design of two separable elements introduces an extra source of margin in the total tolerance chain of the hand blender. Tolerance causes noise and vibration, results in power loss and may lead to wear, damage and early failure.